Hot air ovens of this kind are known, for example, from U.S. Pat. 4,155,294. Hot air ovens are being used in increasing quantities for the preparation of deep-frozen foods, e.g. french fries, because the usual preparation in a deep fryer is meeting with increasing disapproval due to the high fat content of the prepared food. In contrast, preparation in a current of hot air is advantageous, insofar as the fat content of the finished food is concerned, but it also produces a resulting improvement in flavor.
In the known hot air ovens, a basket for containing the food is inserted into the cooking chamber, which basket is made of a stainless steel wire mesh welded into a frame made of angled sections so that a block-shaped basket is produced, which has a square cross section in the direction of the rotational axis and is open on one end. This basket can be removed from the hot air oven for filling, can then be loaded via its open end with the food to be prepared, and reinserted into the oven, wherein a covering sieve closes the open upper end of the basket so that the food cannot fall out when the basket is rotated around its rotational axis. These wire baskets have serious disadvantages. The cleaning of this kind of basket is very difficult since food residues and other encrustations can adhere between the wires of the wire mesh that rest against each other at a crossing point, and can only be removed from there with difficulty. Furthermore, impurities adhere chiefly in the corners of the block-shaped basket because the wire mesh is welded into the angled sections there, resulting in a device that is very difficult to clean. This problem leads to the fact that the cleaning of the basket, which is required from a hygienic standpoint, is neglected.
A further problem in hot air ovens is the preparation time. In particular in snack bars, a particularly rapid food preparation is sought. For this, it is required that the hot air in the inner chamber of the hot air oven can flow favorably through the basket in order to effectively cook and roast the food. The through flow occurs approximately in the radial direction of the basket, so that the open cross section of the wire sieve or wire grating used should be noted. Since the flow does not always occur perpendicular to the wire grating, but also at times at a certain angle due to the rotation of the basket, the free cross section should also be considered at this angle of 45.degree. for example. In the course of this, it is determined that the free cross-section of a wire sieve drops relatively quickly when there is a deviation from the perpendicular